National Prevalence and Associated Outcomes of Substance Use in Scooter-Related Trauma

Introduction

Positioned as an accessible and environmentally-friendly option for short-distance travel, electric scooters have gained rapid adoption across urban areas worldwide. ¹ However, this surge in scooter use has been accompanied by significant public health concerns, with health care systems reporting a notable rise in scooter-related injuries (SRI) and associated health care costs. ² Prior work has highlighted the increase in SRI to have placed additional strains on emergency services, especially among riders who neglect protective gear. ³ Moreover, given the vulnerabilities posed by factors such as the rider’s balance, speed and road condition, injury prevention strategies are particularly relevant in the context of electric scooters. ⁴ To date, regulations and advocacy surrounding the safety of electric scooters remain sparse, while specific risk factors for SRI have not been widely disseminated or followed.

Despite growing recognition of the adverse outcomes associated with SRI, a significant gap in research regarding the role of substance use (SU) in such accidents remains. Encompassing both alcohol and illicit or prescription drug consumption, SU is known to impair key cognitive and physical functions that are critical for the safe operation of micromobility devices.^4,5 A prior meta-analysis has shown that 1 in 5 patients with SRI are intoxicated by drugs or alcohol, noting the increased risk of TBI in those with positive alcohol screening. ⁶ Impairing balance and executive function, SU may increase the odds of traumatic injuries sustained while using scooters. Thus, characterization of SU in scooter injuries is necessary for the development of targeted prevention strategies and legislative policies aimed at reducing the risks associated with impaired riding.

In the present analysis, we examine temporal trends in substance use among a national cohort of patients admitted for SRI. We hypothesized SU to be independently associated with increased odds of traumatic brain injuries and resource utilization.

Methods

This was a retrospective cohort study using the 2016-2021 National Inpatient Sample (NIS). ⁷ All patients 18-64 years of age hospitalized for SRI with or without SU (alcohol, opioid, marijuana, cocaine) were identified using relevant International Classification of Diseases, Tenth Revisions (ICD-10) codes. Patient and hospital characteristics, including age, gender, race, insurance status, and hospital bed size, were defined according to the NIS data dictionary. Patient age was grouped into 18-25, 26-40, and 41-64 years to facilitate comparison. Records missing key variables such as age, gender, race, and mortality were excluded from the analysis (2.9%). The burden of comorbidities was captured using the Elixhauser Comorbidity Index, while injury severity was measured using the Trauma Mortality Prediction Model (TMPM).^8,9 Traumatic brain injury (TBI) was defined as a composite of concussion, intracranial hemorrhage, and cranial fracture. As previously described in the literature, patients undergoing any major operations (neurologic, head and neck, ophthalmologic, thoracic, cardiac, gastrointestinal, genitourinary, vascular, and orthoplastic) were identified using appropriate ICD-10 procedure class codes. ¹⁰ The primary outcome of interest was temporal trends of electric scooter injuries and associated SU. In-hospital mortality, perioperative complications (cardiac, respiratory, and infectious), index hospitalization length of stay (LOS), hospitalization costs, and non-home discharge were secondarily examined.

The Pearson’s Chi-square and Kruskal-Wallis tests were used to compare patient characteristics. Nonparametric rank-based tests were used to assess temporal trends (nptrend). Multivariable regression was used to evaluate the association between SU and outcomes of interest. Regression outputs are reported as adjusted odds ratios (AOR) or beta coefficients (β) both with 95% confidence intervals (95% CI), as appropriate. All statistical analyses were performed using Stata 16.1 (StataCorp, College Station, TX).

Results

Of an estimated 7350 patients admitted for SRI, 1820 (24.8%) had concomitant SU. The prevalence of SRI hospitalization increased significantly from 330 cases in 2016 to 2705 in 2021 (nptrend <0.001). Concurrently, alcohol use among patients increased significantly among patients with SRI in 18-25 (2016: 0% vs 2021: 19.8%, nptrend <0.001) and 26-40 (2016: 0% vs 2021: 25.1%, nptrend <0.001) age groups. Opioid use among SRI patients also significantly increased in 26-40 (2016: 0% vs 2021: 3.7%, nptrend <0.001) and 41-64 (2016: 2.6% vs 2021: 3.8%, nptrend <0.001) age groups (Figure 1). Additionally, those with SU more frequently had TBI (39.3 vs 21.4%, P < 0.001) and required major operation (44.8 vs 61.1%, P < 0.001), while injury severity measured by TMPM was greater in patients with SU (13.2 [0.1-53.0] vs 2.5 [0.1-19.8], P < 0.001). Compared to others, those with SU had a similar distribution of age groups (P = 0.14), while more commonly being male (78.0 vs 64.1%, P < 0.001) and White (67.0 vs 60.1%, P = 0.03). Those with SU were more likely to have head/neck injuries (28.6 vs 14.3%, P < 0.001) (Table 1).

OPEN IN VIEWER

Figure 1.

Temporal trends in prevalence of alcohol, opioid, marijuana and cocaine use among SRI from 2016 to 2021 stratified by age group: 18-25 years (A), 26-40 years (B), and 41-64 years (C).

OPEN IN VIEWER

Table 1.

Baseline Characteristic of Patients Hospitalized for Scooter-Related Injury With Substance Use (SU) and Those Without (Non-SU). TMPM, Trauma Mortality Prediction Model.

	SU (N = 1820)	Non-SU (N = 5530)	P-Value
Elixhauser score	2 [1-3.5]	1 [0-2]	<0.001
TMPM score	13.2 [0.1-53.0]	2.5 [0.1-19.8]	<0.001
Male (%)	78.0	64.1	<0.001
Age group (%)			0.14
18-25 years	11.4	14.8
26-40 years	36.1	31.5
41-64 years	52.5	53.7
Race (%)			0.03
White	67.1	60.8
Black	10.9	13.1
Hispanic	15.8	15.5
Asian/Pacific islander	1.1	4.3
Others a	5.1	6.3
Injury location (%)			<0.001
Head/Neck	23.6	14.3
Torso	6.8	5.0
Abdomen	5.1	5.0
Upper extremity	26.1	23.8
Lower extremity	38.4	51.9

^aOther race included native Americans and multiracial cohorts.

Patients with SU and non-SU exhibited similar in-hospital mortality (0.5 vs 0.3%, P = 0.43) (Table 2). Compared to others, SU patients more commonly suffered from TBI (39.3 vs 21.4%, P < 0.001) but less frequently had long bone fractures (22.5 vs 36.0%, P < 0.001) and underwent major operations (44.8 vs 61.1%, P < 0.001). In-hospital mortality and rates of perioperative complications were similar between SU and non-SU cohorts, as well as LOS (3 [1-5] vs 3 [2-5] days, P = 0.97), hospitalization costs ($15,300 [$8700-26,500] vs $15,300 [$9800-24,300], P = 0.76) and non-home discharge rates (24.3 vs 29.5%, P = 0.07).

OPEN IN VIEWER

Table 2.

Baseline Characteristic in Patients Hospitalized for Scooter-Related Injury With Substance Use (SU) and Those Without (Non-SU).

	Unadjusted a			Adjusted b
	SU (N = 1820)	Non-SU (N = 5530)	P-value	Estimates	95% CI
Mortality	0.5	0.3	0.43	1.17	0.63-1.68
Traumatic brain injury	39.3	21.4	<0.001	1.65*	1.16-2.37
Long bone fracture	22.5	36.0	<0.001	0.73	0.52-1.05
Ligamentous injury	1.9	3.3	0.16	0.62	0.22-1.37
Major operation	44.8	61.1	<0.001	0.99	0.59-1.68
Perioperative complication	13.2	9.9	0.08	1.60*	1.05-2.45
LOS (Days)	3 [1-5]	3 [2-5]	0.97	1.0	0.1-2.1
Hospitalization cost ($1000)	15.3 [8.7-26.5]	15.3 [9.8-24.3]	0.76	4.7*	0.3-9.4
Non-home discharge	24.3	29.5	0.07	0.76	0.54-1.07

Following risk adjustment, the odds of mortality were similar. SU and non-SU also had similar odds of long bone fracture and ligamentous injury. However, those with SU had an increased risk of TBI (AOR 1.65, 95%CI 1.16-2.37) and perioperative complications (AOR 1.60, 95% CI 1.05-2.45). While SU status was not associated with incremental LOS, SU had incremental index hospitalization costs by $4700 (95% CI $300-9400). The odds of non-home discharge were similar among study cohorts.

Discussion

Since the introduction of shared electric scooter systems targeting urban centers, the incidence of SRI has significantly increased over the past decade. In the present study, we showed a notable rise in the prevalence of both alcohol and opioid usage among scooter riders during the study period. Scooter riders with SU were found to have experienced more severe injuries, with a substantially higher risk of TBI compared to their sober counterparts. Furthermore, patients with SU had incremental hospitalization costs while having similar LOS compared to those without SU. These findings align with prior studies that have documented the growing burden of electric scooter injuries on trauma systems.^11,12 Given the broader implications for resource allocation in trauma care as well as public safety, our findings warrant further discussion.

The prevalence of SRI requiring hospitalization has increased more than 8-fold over the study period, rising from approximately 330 cases in 2016 to nearly 2700 in 2021. This substantial rise underscores the growing public health challenge associated with the widespread adoption of shared-scooter ridership in the US. While prior work has reported that 5.2% of scooter riders presenting to the emergency department had alcohol intoxication, our study found that over 16% of adults hospitalized for SRI exhibited alcohol use. ³ Moreover, increase in the temporal trend of alcohol use among scooter riders aged 18-40 suggest that unrestricted alcohol consumption and scooter use contribute to more severe injuries and higher hospitalization rates. Additionally, we showed a notable increase in opioid use among hospitalized scooter riders over the age of 25. This finding aligns with broader trends of the opioid crisis, where nearly 3.4% of the population report opioid misuse, while prescription opioid exposure has increased by 93% annually over the past decade. ¹³ These findings suggest that both the opioid epidemic and unrestricted alcohol use among scooter riders may exacerbate the public health burden associated with SRI. Taken together, our findings underscore the urgent need for targeted interventions aimed at reducing synergistic risks posed by scooter riding and substance use.

The availability and marketing of both alcohol and shared-scooter systems targeted in urban areas amplify the risks of SRI.^14,15 Urban environments, often characterized by dense traffic and mixed pedestrian-vehicular roadways, are particularly conducive to collisions, thereby increasing the likelihood of SRIs. The present study showed SU to be associated with increased odds of TBI among scooter riders. Importantly, a previous study has shown that micromobility users were over 2 times less likely to wear helmets under the influence of alcohol. ¹⁶ Additionally, current legislation regarding protective gear among scooter riders varies significantly across the state, and several states (California, New York, Massachusetts, Indiana, Colorado, Nevada, and Minnesota) only require helmets among those <18 years of age. ¹⁷ In the present analysis, we noted individuals with SU to be more likely to sustain head and neck injuries compared to others, with over 39% of SU patients experiencing TBI. Alcohol and drug use may compromise cerebellar function, impairing balance, reaction time, and proprioception, all of which may contribute to an increased likelihood of head injury.^18,19 Beyond acute head trauma, elevated blood alcohol concentration has been shown to result in worse neurologic outcomes in patients with TBI. ²⁰ Given the increased risk of TBI in SRI patients with alcohol and drug use, implementing community programs aimed at reducing SU and prohibiting scooter share among intoxicated riders are warranted.

From a health economics perspective, our analysis found that patients with SU had significantly higher hospitalization costs compared to those without SU despite having comparable LOS. Increased costs may be attributed to additional resource utilization needed to care for patients with SU, such as increased nurse staffing, specialized interventions, and medications required for SU management. Prior work has estimated the total annual hospital costs attributable to substance use disorders at $13.2 billion, with alcohol and opioid use disorders contributing $7.6 and 2.2 billion, respectively. ²¹ Indeed, SU has extensive societal and economic repercussions, including increased rates of DUI and injuries as well as higher opportunity costs associated with missed work hours and elevated health care expenditure. ²² The additional resource demands associated with intoxicated scooter riders may further strain the already overburdened trauma care systems in the urban national regions. Addressing such growing public health concerns requires a multifaceted approach that focuses on injury prevention strategies. Future efforts to improve road infrastructure, community education regarding scooter safety, and legislative reforms at the local, state, and national levels are necessary to enhance injury prevention and substance use control. Such measures may reduce the economic burden of SRI and contribute to fostering a safer community.

The present study has several important limitations, including those inherent to its retrospective nature. We were unable to ascertain granular physiologic or imaging data. Additionally, substance use was based on administrative codes. Importantly, the lack of specificity in ICD-10 coding for scooter types further limited our ability to distinguish shared-system scooters from privately owned scooters. Additionally, because the NIS is restricted to inpatient admissions, emergency department utilization data was not captured. Despite limitations, our study used a robust statistical methodology and the largest national database to analyze temporal trends as well as clinical and financial outcomes in SU patients hospitalized for SRI management.

The significant rise in scooter-related injuries, coupled with the increasing prevalence of substance use among riders, underscores a critical challenge for the health care system. Our findings demonstrate how the interplay between SRI and SU exacerbates clinical patient outcomes while placing additional strain on trauma care resources. Given that these patients often arrive at the trauma bay, trauma surgeons play a vital and frequent role in their management, directly impacting patient recovery. To address this growing issue, targeted injury prevention strategies, public health education, and legislative reforms are necessary to reduce substance use and mitigate SRIs.